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Biomedical subjects

Koji Nishimura

Publications and source records attributed to Koji Nishimura.

7 recordsLinked to original sources
PubMed2003

Abietic acid activates peroxisome proliferator-activated receptor-gamma (PPARgamma) in RAW264.7 macrophages and 3T3-L1 adipocytes to regulate gene expression involved in inflammation and lipid metabolism.

Abietic acid is one of the terpenoids, which are multifunctional natural compounds. It has been reported that abietic acid suppresses effects on inflammation. However, the mechanism underlying the anti-inflammatory effects remains unclear. The present work indicates that abietic acid suppresses the protein expression of tumor necrosis factor-alpha and cyclooxygenase 2, which are involved in inflammation, in lipopolysaccharide-stimulated macrophages. Moreover, this effect resembles that of thiazolidinedione, a synthetic peroxisome proliferator-activated receptor-gamma (PPARgamma) ligand. Indeed, abietic acid activates PPARgamma in luciferase reporter assays. The activity of abietic acid induces PPARgamma target gene expression in RAW264.7 macrophages and 3T3-L1 adipocytes. These data indicate that abietic acid is a PPARgamma ligand and that its anti-inflammatory effect is partly due to the activation of PPARgamma in stimulated macrophages. The present work suggests a novel possibility that abietic acid, a naturally occurring compound, can be used not only for anti-inflammation but also for regulating lipid metabolism and atherosclerosis.

3T3 Cells↗
PubMed2003

Single nucleotide polymorphisms in the human complement C6 and C7 genes.

We analyzed the single nucleotide polymorphisms (SNPs) in the sixth (C6) and the seventh (C7) component genes of the complement system in a sample of the Japanese population, using polymerase chain reaction (PCR)-based methods and PCR direct sequencing. SNPs in the C6 gene studied here are as follows: A413C in exon 3, T1674C in exon 10, T7145A in exon 13, G[357+32]A in intron 2, and G[503-78]A in intron 3. We confirmed that nt413A and nt413C were associated with C6A and C6B, respectively. The result of the nt2145 typing showed that two subtypes exist in the C6B allotype. The SNP of G[357+32]A in intron 2 could be analyzed by using the PCR-RFLP method with HinfI. Allele frequencies in the Japanese population were found to be *G=0.920 and *A=0.080. SNPs in the C7 gene are as follows: T382C in exon 4, G1166C and A1258C in exon 9, and G[+10]A in intron 13. Nt382C and nt1258C would be responsible for C7-5 (=C7-3) and C7-4 allotypes, respectively.

Complement C6↗
PubMed2003

Short tandem repeat typing in exon 1 of the androgen receptor gene.

Exon 1 of the androgen receptor (AR) gene on the X chromosome contains a polymorphic CAG trinucleotide short tandem repeat. We describe here the rapid and reliable method of typing CAG repeats using electrophoresis, with denaturing polyacrylamide gel and an allelic ladder marker. Twenty-one alleles (the repeat number ranges from 13 to 35) were found using CAG repeat typing in normal Japanese individuals (83 males and 82 females). The allelic diversity (h) calculated was h=0.889, illustrating that CAG repeats at the AR locus is a highly polymorphic system.

Chromosomes, Human, X↗
PubMed2003

A-elute alleles of the ABO blood group system in Japanese.

The ABO blood group system is important in forensic genetics, as well as transfusion medicine. Since the elucidation of the molecular basis of ABO gene regulation, nucleotides of variant alleles or suballeles have been analyzed by polymerase chain reaction (PCR)-based methods and sequencing. Ael (A-elute) is one of the subgroups of A in the ABO system. By analyzing the suballeles responsible for Ael phenotype by PCR-RFLP and PCR direct sequencing, we found seven types of Ael allele. The allele frequency of ABO*Ael in a Japanese population was calculated to be 0.0049.

ABO Blood-Group System↗
PubMed2002

Molecular bases for human complement C7 polymorphisms, C7*3 and C7*4.

Complement C7 is one of the components of membrane attack complex (MAC) generated by the terminal complement cascade. C7 protein is polymorphic and most of its polymorphisms have been identified using isoelectric focusing (IEF), which detects protein charge differences. To date, the molecular bases of the polymorphisms detected by IEF have not been determined. In this paper, we describe the structural bases of two C7 IEF-detected polymorphisms, C7*3 and C7*4, both of which are common in Asian populations. C7*3 resulted from substitution of cysteine (Cys) at amino acid residue 106 by charged arginine (Arg; C106R), while charged lysine (Lys) at amino acid residue 398 was replaced by neutral glutamine (Gln; K398Q) in C7*4. As C7*3 is hypomorphic, it is important to study its possible associations with diseases such as immunological disorders and infections. We present genetic bases for this C7 polymorphism, which we determined using polymerase chain reaction (PCR)-based genotyping, a simple and accurate method suitable for large-scale studies.

Base Sequence↗
PubMed2002

Characterization of rat liver bile acid acyl glucuronosyltransferase.

Recent studies have suggested that bile acid acyl glucuronides form covalently bound protein adducts which may cause hypersensitivity reactions and increased morbidity in patients. Although the preferential biosynthesis of the acyl glucuronides has been known, the characterization of hepatic bile acid acyl glucuronosyltransferase has not yet been clearly elucidated. We have investigated the substrate specificity of the hepatic bile acid acyl glucuronosyltransferase using five common bile acids as substrates. The glucuronidation rate was dependent on the number of the hydroxy group on the steroid nucleus and mono-hydroxylated lithocholic acid, the more lipophilic common bile acid, was most effectively metabolized into its acyl glucuronide. The tri-hydroxylated cholic acid, the more water-soluble common bile acid, barely transformed into its glucuronide. Results showed decreasing of the initial velocity of the acyl glucuronidation with increasing of the concentration of substrate, lithocholic acid, owing to the substrate inhibition of the hepatic bile acid acyl glucuronosyltransferase. The substrate analogues, glycine and taurine conjugated bile acids, which exist in the body fluids in high concentrations, also inhibited the enzyme's activity. In addition, enzymatic reaction products, bile acid acyl glucuronides, also inhibited the activity. These inhibitory mechanisms may be responsible for the low concentration of bile acid acyl glucuronides in urine and may be an important detoxification system in the body.

Animals↗
PubMedDate not supplied

Lymphagenesis correlates with expression of vascular endothelial growth factor-C in colorectal cancer.

Lymphagenesis in gastrointestinal tumors is not well described. To clarify its presence and regulation, we assessed the microlymphatic count (MLC) in colorectal cancer patients. Lymphatic vessels were evaluated by enzyme-histochemistry for 5'-nucleotidase (5'-NA). Since vascular endothelial growth factor (VEGF)-C is reportedly associated with lymphagenesis, the expression of VEGF-C protein was immunohistochemically assessed by the catalyzed signal amplification (CSA) method. MLC of peritumoral lesions was significantly higher than that of non-cancer and intratumoral lesions (p<0.01); it increased where VEGF-C was highly expressed (p<0.01) and increased with the depth of invasion in peritumoral lesions. These results indicate significant findings at peritumoral lesion: that lymphagenesis may be elicited by tumor spread; that VEGF-C expression is associated with lymphagenesis and is a potent factor stimulating lymphagenesis.

5'-Nucleotidase↗